Blow molded case and method and apparatus for creating same

ABSTRACT

A method and apparatus for blow molding a case for housing an object, such as a tool, is disclosed generally comprising first and second mold portions located adjacent each other to create separate cavities for forming base and lid portions of a case and a punch for each portion corresponding to the outline of an object. In certain embodiments, the punch protrudes into the cavity during blow molding to create a sidewall to facilitate a press fit. In some embodiments, additional punches and/or recesses are provided to produce additional apertures or flanges in the walls of the tool case.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for creatingblow molded cases. More specifically, the invention relates to a methodand apparatus for creating double wall cases with a punched area forhousing an object.

BACKGROUND OF THE INVENTION

The use of blow-molding as a method for manufacturing various sorts ofarticles is generally well known. Typically, this process involves theuse of a mold consisting of two separate halves or portions havingcavities of particularly desired shapes and sizes. Usually, one extrudesa large-diameter, sealed tube of molten material (commonly referred toas a “parison”), places the tube between the mold halves, and closes themold around the tube. Fluid pressure is then introduced into the tube,forcing the molten tube against the walls of the cavities, conformingthe tube to the shape thereof. The pressure is maintained until themolten material cools and solidifies. The pressure is then released, themold halves are pulled apart, and the hardened article is ejectedtherefrom.

One such article that is commonly manufactured in this manner is doublewall cases. By producing cases in this manner, one is able to produce adevice that is capable of carrying and protecting tools placed insidethe case that has a multitude of desirable physical characteristics—suchas rigidity, scuff resistance, and impact absorption—yet that isrelatively inexpensive to manufacture. Typically, these cases will beformed using the process described above, where one mold half forms theexterior of both the base and lid portions of the case, while the othermold half forms the interior of both base and lid portions. Usually, themold half forming the exterior of the case forms a wall with a smooth,attractive shape, while the mold half that forms the interior of thecase is often molded with compartments to hold specific contents, suchas, for example, a pistol-type soldering iron and various tipstherefore. In fact, a particular advantage of manufacturing cases inthis way is that the walls formed by the two mold halves do not need tomatch, as the space between these walls is filled with air.

One disadvantage of these cases, however, as that, due to their doublewall nature, they tend to be both heavy and cumbersome. Accordingly, ithas been suggested to cut out sections of the interior walls of the casein order to utilize the wasted volume of space between the double walls.By doing so, the case can be made smaller in light of the fact that thispreviously unused space is now being used to house the tool. Moreover,by removing sections of the walls, the case also decreases significantlyin weight. As a result, it is also much easier to mold the design of theinterior of the case, as it is no longer necessary to create deep moldedcompartmentation, and fewer molding rejects also result.

An example of this approach is disclosed in U.S. Pat. No. 3,317,955 toSchurman, et al., which discloses the earliest known double wall caseblow-molded case, illustrating a rectangular cutout of most of theinside wall of the base portion. Another example is disclosed in U.S.Pat. No. 3,327,841 to Shurman, et al., which illustrates a partialcutout shaped to accommodate the outline of a pistol-type soldering gun.The gun is further supported by a cradle molded in the outside wall ofthe base portion of the case, while the space under the uncut portion ofthe inside base is usable for storage of an electric cord, therebymaximizing the utilization of what was previously wasted unused space.

However, one problem with removing wall sections in blow-molded cases asshown in these disclosures is that, because the blow molding processinvolves the use of a parison with a continuous, unbroken surface, themold itself cannot produce any holes in the blow-molded wall other thanthe hole or holes through which the fluid pressure is introduced.Therefore, removing these sections typically involves an additionalmanufacturing step, where these wall sections are cut or burned afterthe blow molding process is completed and the case has been ejected fromthe mold. For example, cutting the inner wall was often accomplishedwith the use of a small circular saw blade mounted to a router andguided by a molded vertical lip surrounding the area to be cut. Therouter was fixed and the case was moved around the router axis by handor by mechanical means. Round holes are often cut with hole saws, oroccasionally, are burned. Cutting or burning these holes after the blowmolding process is completed, however, requires additional tooling andadditional manufacturing steps, entailing further difficulty, time, andexpense. Moreover, the process produces unwanted sawdust or charredmaterial around the cutout lip.

Another disadvantage of removing the wall sections after the blowmolding process is complete is that the blow-molding process itselftakes an unnecessarily long time. Generally, when a double wall case isblow molded using injections of fluid through one or more needles, theamount of air that can be circulated within the case is severelylimited. Accordingly, the amount of heat that can be removed from theinside plastic walls is also limited, and thus, because these walls mustbe cooled before the part can be ejected from the mold, the blow-moldedcycle is slow. Similarly, draining the blowing fluid through one or moreneedle orifices at the end of the blowing cycle is a relatively slowprocess, and because the case cannot be ejected from the mold until heinternal air pressure has returned nearly to atmospheric pressure, theprocess is somewhat slow.

What is desired, therefore, is a blow-molded case that is double walled,but is not heavy or cumbersome. What is also desired is a case that iseasy and inexpensive to manufacture. What is further desired is ablow-molded case that does not produce residual sawdust and/or charredplastic. What is also desired is a case that does not require a longblow molding cycle.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide adouble wall case that utilizes the space between the walls of the case.

It is a further object of the present invention to provide a double wallcase that does not require additional manufacturing steps after theblowing cycle.

It is yet another object of the present invention to provide a doublewall case that does not require cutting or burning during manufacture.

It is still another object of the present invention to provide a doublewall case that does not require a long time to cool the inside plasticwalls of the case during manufacture.

It is yet another object of the present invention to provide a doublewall case that does not require a long time to drain blowing fluid fromthe case during manufacture.

In order to overcome the deficiencies of the prior art and to achieve atleast some of the objects and advantages listed, the invention comprisesan apparatus for creating a blow-molded case for housing an object,including a mold comprising first and second mold portions that, whenlocated adjacent each other, have first and second mold surfaces atleast partially defining first and second cavities, the cavities havingfirst and second cavity surfaces, respectively, against which first andsecond walls of the blow-molded case are blown, respectively, duringblow molding, and a first punch having a punching surface at least partof which corresponds to at least part of the outline of the object,wherein, when the first punch is in an unactivated position, the firstcavity surface includes the first mold surface and at least part of thefirst punch and, when the first punch is in an activated position, atleast part of the first punch is extended past the first wall of theblow-molded case and inside the first cavity such that a first hole, atleast part of which corresponds to at least part of the outline of theobject, is created in the first wall of the blow-molded case.

In another embodiment, the invention comprises a method for creating ablow-molded case for housing an object, including providing a moldhaving first and second mold portions, providing a first punch, whereinthe first punch has a punching surface at least part of whichcorresponds to at least part of the outline of the object, moving thefirst mold portion adjacent to the second mold portion, thereby at leastpartially enclosing first and second cavities having first and secondcavity surfaces, respectively, blowing a first wall of the blow-moldedcase against the first cavity surface and a second wall of theblow-molded case against the second cavity surface, and extending atleast part of the first punch through the first wall of the blow-moldedcase and into the first cavity, thereby creating a first hole in thefirst wall of the blow-molded case.

In yet another embodiment, the invention comprises a blow-molded casefor housing an object, including a double wall base portion having afirst cavity for housing at least part of the object, a double wall lidportion connected to the base portion, the lid portion having a secondcavity for housing at least part of the object, and wherein one of thebase and lid portions has a first punched hole at least part of whichcorresponds to at least part of the outline of the object for receivingthe object.

In still another embodiment, the invention comprises a method forcreating a blow-molded case for housing an object, including moving afirst mold portion adjacent to a second mold portion, thereby creatingfirst and second cavities, blowing first and second walls of theblow-molded case against the first and second cavities, respectively,and punching a hole, at least part of which corresponds to at least partof the outline of the object, in the first wall of the blow-molded case.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a tool case in the open position madein accordance with the invention.

FIG. 1B is a perspective view of the tool case of FIG. 1 in the closedposition.

FIG. 2 is a perspective view of an apparatus in accordance withinvention for making the tool case of FIG. 1.

FIG. 3A is a side view of one embodiment of the apparatus of FIG. 2 inan open position.

FIG. 3B is a side view of the apparatus of FIG. 3A in a closed position.

FIG. 4A is a cut-away, cross-sectional view of part of one embodiment ofthe apparatus of FIG. 3B where a punch is in an unactivated position.

FIG. 4B is a cut-away, cross-sectional view of the apparatus of FIG. 4Awhere a punch is in an activated position.

DETAILED DESCRIPTION OF THE DRAWINGS

The basic components of one embodiment of a double wall blow molded toolcase in accordance with the invention are illustrated in FIG. 1A. Asused in the description, the terms “top,” “bottom,” “above,” “below,”“over,” “under,” “above,” “beneath,” “on top,” “underneath,” “up,”“down,” “upper,” “lower,” “front,” “rear,” “back,” “forward” and“backward” refer to the objects referenced when in the orientationillustrated in the drawings, which orientation is not necessary forachieving the objects of the invention.

The case 10 includes a double wall base portion 12 and a double wall lidportion 14. The base portion 12 has a punched hole 20 in its inner wall22 that corresponds to the outline of an object, such as a tool, to behoused by the tool case 10. Accordingly, the hole 20 and the spacebetween the inner wall 22 and the outer wall 24 provide a cavity 26 inwhich the tool can be placed.

Similarly, the lid portion 14 includes a punched hole 30 in its innerwall 32. Accordingly, the hole 30 and the space between the inner wall32 and outer wall 34 provide a cavity 36 for accommodating the top ofthe tool when the tool case 10 is closed, as shown in FIG. 1B. Incertain advantageous embodiments, the hole 30, like the hole 20,corresponds to the outline of the tool to provide a more secure fit.

In some embodiments, a sidewall 40 substantially perpendicular to theplane of the punched hole 20 runs along the perimeter of the hole 20,providing a press fit insertion of the tool into the cavity 26.Additionally, in certain embodiments, an additional punched aperture 42,which may be a through hole or a blind hole, is provided to permitaccessories—such as, for example, drill bits, or, as another example, apower cord—to be stored therein. In some of these embodiments, a flange44 is provided adjacent the hole 20 and aperture 42 in order to providefor greater rigidity. Also, in certain embodiments, at least one boss 46in the outer wall 24 is provided to engage a particular shape oraperture in the tool, such as a handle. Depending on the particularembodiment and on the particular tool for which the tool case 10 isdesigned, one or more of the above-described features may be provided inthe lid portion 14 in addition to, or in lieu of, the presence of thesefeatures in the base portion 12.

As illustrated in FIG. 2, an apparatus for creating the tool case 10 ofFIG. 1 comprises a mold 50 including a first mold portion 52 and asecond mold portion 54. As shown in FIGS. 3A-B, the first mold portion52 includes first and second punches 56, 58 having first and secondpunching surfaces 66, 68, respectively. When the first and second moldportions 52, 54 are separated, such as when a parison is being disposedin the mold 50, the first and second punches 56, 58 are in anunactivated position, as shown in FIG. 3A. As illustrated in FIG. 3B,when the first and second mold portions 52, 54 are moved adjacent eachother (i.e., when the mold 50 is closed), the first and second punches56, 58 remain in the unactivated position while the parison is beinginjected with blowing fluid. Accordingly, portions of the first andsecond punches 56, 58 form part of the surfaces against which the wallsof the blow molded case are blown. Later, when it is desired to punchholes in the walls of the blow molded case, the first and second punches56, 58 are moved to an activated position, as shown in phantom in FIG.3B.

The operation of the mold portion 52, 54 and punches 56, 58 isillustrated in FIGS. 4A-B. When the first mold portion 52 is adjacentthe second mold portion, a cavity 70 is formed in each of the base andlid portions of the mold 50. For example, referring to FIG. 4A, when thepunch 56 is in the unactivated position, the cavity 70 has a cavitysurface 80 comprised of the mold surface 72 of the mold portions 52, 54and part of the punch 56. This cavity surface 80 defines the cavity 70.When blowing fluid is injected into the parison, the wall of the blowmolded case is blown against the cavity surface 80.

After a predetermined time interval, the punch 56 is moved from anunactivated position to an activated position, as illustrated in FIG.4B. When this occurs, the punch 56 is extended past the wall of the blowmolded case and into the cavity 70, thereby creating a hole in the wallof the blow molded case. The punch 56 has a punching surface 76corresponding to the outline of the tool to be housed in the tool case10, and thus, a hole in the shape of the tool is created in the wall ofthe blow molded case 10. In certain advantageous embodiments, thepunching surfaces of both punches 56 and 58 correspond to the outline ofthe tool. By removing a large section of the walls of the blow moldedcase 10 at this stage, drainage of the blowing fluid is almostinstantaneous. Similarly, large volumes of air can be quickly circulatedinside the case 10, quickly cooling and solidifying the walls of thecase. In these ways, the time required for the blow molding cycle isgreatly reduced.

In some embodiments, when the punch 56 is in the unactivated position,the punch 56 protrudes out beyond the mold surface 72 into the cavity70, as shown in FIG. 4A. As a result, when the wall of the blow moldedcase 10 is blown against the cavity surface 80 (which includes part ofthe punch 56), the wall of the case 10 is formed around the punch 56. Inthis way, a recessed portion is formed in the wall of the case.Accordingly, when the punch is moved to the activated position (therebypunching the tool-shaped hole 20 in the wall of the case 10 as shown inFIG. 4B) the sidewall 40 remains along the perimeter of the tool-shapedhole 20. This permits a tighter, press-fit insertion of the tool intothe cavity 26.

In some embodiments, the second mold portion 54 includes a boss 84 thatextends into the cavity 70. Accordingly, when the wall of the blowmolded case is blown against the cavity surface 80, a boss, such as boss46, is created. In certain of these embodiments, the boss 84 correspondsto the outline of an aperture of the tool to be housed in the case 10,such as a handle.

In certain advantageous embodiments, the first mold portion 54 includesa boss 86 so that the wall of the blow molded case 10 is formedtherearound in a manner similar to boss 84, thereby producing anaperture in the wall of the case 10, such as aperture 42. In some ofthese embodiments, the boss 86 is specifically configured to produce anaperture adapted to receive an accessory of the tool, such as a powercord, drill bits, etc.

In some embodiments, at least one additional punch is provided inaddition to the first and second punches 56, 58. Like punches 56, 58,these additional punches, when in an unactivated position, form part ofthe cavity surface 80 and, when in an activated position, extend outbeyond the mold surface 72 to create an aperture in the wall of the blowmolded case. Depending on the particular tool to be housed in the case10 and the particular function desired, the aperture can be a throughhole or a blind hole, and can be specifically configured to produce anaperture adapted to receive an accessory of the tool.

In certain advantageous embodiments, the mold surface 72 includes arecess 88 adjacent the punch 56 so that, when the wall of the blowmolded case is blown against the mold surface 72, flange 44 is formed,thereby providing greater rigidity to the inner wall 32 of the case 10.

It should be understood that the foregoing is illustrative and notlimiting, and that obvious modifications may be made by those skilled inthe art without departing from the spirit of the invention. Accordingly,reference should be made primarily to the accompanying claims, ratherthan the foregoing specification, to determine the scope of theinvention.

1. An apparatus for creating a blow-molded case for housing an object,comprising: a mold comprising first and second mold portions that, whenlocated adjacent each other, have first and second mold surfaces atleast partially defining first and second cavities, the cavities havingfirst and second cavity surfaces, respectively, against which first andsecond walls of the blow-molded case are blown, respectively, duringblow molding; and a first punch having a punching surface at least partof which corresponds to at least part of the outline of the object,wherein, when said first punch is in an unactivated position, the firstcavity surface includes the first mold surface and at least part of saidfirst punch and, when said first punch is in an activated position, atleast part of said first punch is extended past the first wall of theblow-molded case and inside the first cavity such that a first hole, atleast part of which corresponds to at least part of the outline of theobject, is created in the first wall of the blow-molded case.
 2. Theapparatus as claimed in claim 1, further comprising a second punch,wherein, when said second punch is in an unactivated position, thesecond cavity surface includes the second mold surface and at least partof said second punch and, when said second punch is in an activatedposition, at least part of said second punch is extended past the secondwall of the blow-molded case and inside the second cavity such that asecond hole is created in the second wall of the blow-molded case. 3.The apparatus as claimed in claim 2, wherein said second punch has apunching surface at least part of which corresponds to at least part ofthe outline of the object, such that, when said second punch is movedfrom the unactivated position to the activated position, at least partof the second hole corresponds to at least part of the outline of theobject.
 4. The apparatus as claimed in claim 1, wherein the outline ofthe object is the outline of a tool.
 5. The apparatus as claimed inclaim 1, wherein the full perimeter of the first hole corresponds to thefull outline of the object.
 6. The apparatus as claimed in claim 1,wherein, when said first punch is in the unactivated position, part ofsaid first punch is protruding out beyond the first mold surface intothe first cavity such that, when said first punch is in the unactivatedposition, the first wall of the blow-molded case is formed therearoundand, when said first punch is in the activated position and the firsthole has been created, a sidewall corresponding to the outline of theobject exists along the perimeter of the hole.
 7. The apparatus asclaimed in claim 1, wherein the second mold portion includes at leastone boss extending into at least one of the first and second cavitiessuch that at least one of the first and second walls of the blow-moldedcase is formed therearound.
 8. The apparatus as claimed in claim 7,wherein the outer surface of at least one boss corresponds to an outlineof an aperture in the object.
 9. The apparatus as claimed in claim 1,wherein the first mold portion includes at least one boss extending intoat least one of the first and second cavities such that at least one ofthe first and second walls of the blow-molded case is formedtherearound.
 10. The apparatus as claimed in claim 9, wherein the outersurface of at least one boss is configured to produce an aperture in atleast one of the first and second walls of the blow-molded case adaptedto receive an accessory of the object.
 11. The apparatus as claimed inclaim 1, further comprising an additional punch, wherein, when saidadditional punch is in an unactivated position, the first cavity surfaceincludes at least part of said additional punch and, when saidadditional punch is in an activated position, said additional punchextends out beyond the first mold surface to a greater extent than whenin the unactivated position such that an aperture is created in thefirst wall.
 12. The apparatus as claimed in claim 11, wherein, when saidadditional punch is in the activated position, said additional punch isextended past the first wall of the blow-molded case and inside thefirst cavity.
 13. The apparatus as claimed in claim 11, wherein saidadditional punch has a punching surface configured to produce anaperture in the first wall of the blow-molded case adapted to receive anaccessory of the object.
 14. The apparatus as claimed in claim 1,wherein the first mold surface includes a recess adjacent said firstpunch such that a flange is formed in the first wall of the blow-moldedcase adjacent the first hole.
 15. The apparatus as claimed in claim 1,wherein the blow-molded case comprises a base portion formed in thefirst cavity and a lid portion formed in the second cavity.
 16. A methodfor creating a blow-molded object case for housing an object, the methodcomprising: providing a mold having first and second mold portions;providing a first punch, wherein said first punch has a punching surfaceat least part of which corresponds to at least part of the outline ofthe object; moving the first mold portion adjacent to the second moldportion, thereby at least partially enclosing first and second cavitieshaving first and second cavity surfaces, respectively; blowing a firstwall of the blow-molded case against the first cavity surface and asecond wall of the blow-molded case against the second cavity surface;and extending at least part of the first punch through the first wall ofthe blow-molded case and into the first cavity, thereby creating a firsthole in the first wall of the blow-molded case.
 17. The method asclaimed in claim 16, further comprising the steps of: providing a secondpunch; and extending at least part of the second punch through thesecond wall of the blow-molded case and into the second cavity, therebycreating a second hole in the second wall of the blow-molded case. 18.The method as claimed in claim 17, wherein the second punch has apunching surface at least part of which corresponds to at least part ofthe outline of the object.
 19. The method as claimed in claim 16,wherein the outline of the object is the outline of a tool.
 20. Themethod as claimed in claim 16, wherein the full perimeter of the firsthole corresponds to the full outline of the object.
 21. The method asclaimed in claim 16, wherein the first mold portion has a first moldsurface at least partially defining the first cavity, further comprisingpositioning the first punch so that part of the first punch isprotruding out beyond the first mold surface into the first cavity whenthe first wall is blown against the first cavity surface such that thefirst wall is formed therearound, and such that, when at least part ofthe first punch is extended through the first wall, thereby creating thefirst hole, a sidewall corresponding to the outline of the object existsalong the perimeter of the first hole.
 22. The method as claimed inclaim 16, wherein the second mold portion includes at least one bossextending into at least one of the first and second cavities such thatat least one of the first and second walls is formed therearound whenblown against at least one of the first and second cavity surfaces. 23.The method as claimed in claim 22, wherein the outer surface of at leastone boss corresponds to an outline of an aperture in the object.
 24. Themethod as claimed in claim 16, wherein the first mold portion includesat least one boss extending into at least one of the first and secondcavities such that at least one of the first and second walls is formedtherearound when blown against at least one of the first and secondcavity surfaces.
 25. The method as claimed in claim 24, wherein theouter surface of at least one boss is configured to produce an aperturein at least one of the first and second walls adapted to receive anaccessory of the object.
 26. The method as claimed in claim 16, whereinthe first mold portion has a first mold surface at least partiallydefining the first cavity, further comprising: providing a additionalpunch in an unactivated position; and extending the additional punch outbeyond the first mold surface to a greater extent than when in theunactivated position, thereby creating an aperture in the first wall.27. The method as claimed in claim 26, wherein the step of extending theadditional punch includes extending the additional punch past the firstwall of the blow-molded case and into the first cavity.
 28. The methodas claimed in claim 26, wherein the additional punch has a punchingsurface configured to produce an aperture in the first wall adapted toreceive an accessory of the object.
 29. The method as claimed in claim16, wherein the first and second mold portions have a first mold surfaceat least partially defining the first cavity, further comprisingproviding a recess adjacent the first punch such that a flange is formedin the first wall adjacent the first hole.
 30. The method as claimed inclaim 16, wherein the blow-molded case comprises a base portion formedin the first cavity and a lid portion formed in the second cavity.
 31. Ablow-molded case for housing an object, comprising: a double wall baseportion having a first cavity for housing at least part of the object; adouble wall lid portion connected to said base portion, said lid portionhaving a second cavity for housing at least part of the object; andwherein one of said base and lid portions has a first punched hole atleast part of which corresponds to at least part of the outline of theobject for receiving the object.
 32. The case of claim 31, wherein theportion not having the first punched hole has a second punched hole foraccommodating the object.
 33. The case of claim 31, wherein at leastpart of the second punched hole corresponds to at least part of theoutline of the object.
 34. The case of claim 31, wherein the outline ofthe object is the outline of a tool.
 35. The case of claim 31, whereinthe full perimeter of the first hole corresponds to the full outline ofthe object.
 36. The case of claim 31, further comprising a sidewallalong the perimeter of the first punched hole.
 37. The case of claim 31,wherein the first cavity has a first cavity surface, the second cavityhas a second cavity surface, and at least one of the first and secondcavity surfaces has at least one boss.
 38. The case of claim 37, whereinthe outer surface of at least one boss corresponds to an outline of anaperture in the object.
 39. The case of claim 37, wherein the innersurface of at least one boss is adapted to receive an accessory of theobject.
 40. The case of claim 31, wherein a wall of the portion havingthe first punched hole has at least one aperture adapted to receive anaccessory of the object.
 41. The case as claimed in claim 31, whereinthe wall of the portion having the first punched hole includes a flangeadjacent the hole.
 42. The case as claimed in claim 31, wherein said lidportion is integrally formed with said base portion.
 43. A method forcreating a blow-molded case for housing an object, the methodcomprising: moving a first mold portion adjacent to a second moldportion, thereby creating first and second cavities; blowing first andsecond walls of the blow-molded case against the first and secondcavities, respectively; and punching a hole, at least part of whichcorresponds to at least part of the outline of the object, in the firstwall of the blow-molded case.
 44. A method as claimed in claim 43,further comprising punching a hole in the second wall of the blow-moldedcase.
 45. A method as claimed in claim 43, wherein at least part of thehole in the second wall of the blow-molded case corresponds to at leastpart of the outline of the object.
 46. A method as claimed in claim 43,wherein the outline of the object is the outline of a tool.
 47. A methodas claimed in claim 43, wherein the full perimeter of the holecorresponds to the full outline of the object.
 48. A method as claimedin claim 43, further comprising forming a sidewall along the perimeterof the hole.
 49. A method as claimed in claim 43, further comprisingforming a boss in at least one of the first and second walls thatextends into at least one of the first and second cavities.
 50. A methodas claimed in claim 49, wherein the step of forming a boss includesforming a boss with an outer surface that corresponds to an outline ofan aperture in the object.
 51. A method as claimed in claim 49, whereinthe step of forming a boss includes forming a boss with an inner surfaceadapted to receive an accessory of the object.
 52. A method as claimedin claim 43, further comprising punching an aperture in the first walladapted to receive an accessory of the object.
 53. A method as claimedin claim 43, further comprising forming a flange in the first wall ofthe blow-molded case adjacent the hole.
 54. A method as claimed in claim43, wherein the blow-molded case comprises a base portion formed in thefirst cavity and a lid portion formed in the second cavity.